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Seismic Performance of 6-Storey Wood-Frame Buildings: Final Report

https://research.thinkwood.com/en/permalink/catalogue2638
Year of Publication
2009
Topic
Seismic
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Author
Ni, Chun
Popovski, Marjan
Organization
FPInnovations
Year of Publication
2009
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Topic
Seismic
Keywords
Mid-Rise
Residential
Building Code
Research Status
Complete
Summary
spIn this report, the seismic performance of 6-storey wood frame residential buildings is studied. Two building configurations, a typical wood-frame residential building and a building to be tested under the NEESWood project, were studied. For each building configuration, a four-storey building and a six-storey building were designed to the current (pre-April 6, 2009) 2006 BC Building Code (BCBC) and to the anticipated new requirements in the 2010 National Building Code of Canada (NBCC), resulting in four buildings with different designs. The four-storey building designed to the current 2006 BC Building Code served as the benchmark building representing the performance of current permissible structures with common architectural layouts. In the design of both four-storey and six-storey buildings, it was assumed that the buildings are located in Vancouver on a site with soil class C. Instead of using the code formula, the fundamental natural period of the buildings was determined based on the actual mass and stiffness of wood-based shearwalls. The base shear and inter-storey drift are determined in accordance with Clauses 4.1.8.11.(3)(d)(iii) and 4.1.8.11.(3)(d)(iv) of BCBC, respectively. Computer programs DRAIN 3-D and SAPWood were used to evaluate the seismic performance of the buildings. A series of 20 different earthquake records, 14 of the crustal type and 6 of the subcrustal type, were provided by the Earthquake Engineering Research Facility of the University of British Columbia and used in the evaluation. The records were chosen to fit the 2005 NBCC mean PSA and PSV spectra for the city of Vancouver. For representative buildings designed in accordance with 2006 BCBC, seismic performance with and without gypsum wall board (GWB) is studied. For representative buildings designed in accordance with the 2010 NBCC, the seismic performance with GWB is studied. For the NEESWood building redesigned in accordance with 2010 NBCC, seismic performance without GWB is studied. Ignoring the contribution of GWB would result in a conservative estimate of the seismic performance of the building. In the 2006 BCBC and 2010 NBCC, the inter-storey drift limit is set at 2.5 % of the storey height for the very rare earthquake event (1 in 2475 year return period). Limiting inter-storey drift is a key parameter for meeting the objective of life safety under a seismic event. For 4-storey and 6-storey representative wood-frame buildings where only wood-based shearwalls are considered, results from both DRAIN-3D and SAPWood show that none of the maximum inter-storey drifts at any storey under any individual earthquake exceed the 2.5% inter-storey drift limit given in the building code. With DRAIN-3D, the average maximum inter-storey drifts are approximately 1.2% and 1.5% for 4-storey and 6-storey buildings designed with 2006 BCBC, respectively. For the NEESWood wood-frame building, none of the maximum inter-storey drifts at any storey under any individual earthquake exceed the 2.5% inter-storey drift limit for 4-storey building obtained from SAPWood and 6-storey building obtained from DRAIN-3D and SAPWood. For any 4-storey building analysed with DRAIN-3D, approximately half of the earthquakes resulted in the maximum inter-storey drifts greater than 2.5% inter-storey limit. This is partly due to the assumptions used in Drain-3D model in which the lumped mass at each storey is equally distributed to all the nodes of the floor. As a result, the total weight to counteract the uplift force at the ends of a wall would be much smaller than that anticipated in the design, thus causing hold-downs to yield and large uplift deformations to occur. Based on the analyses of a representative building and a redesigned NEESWood building situated in the city of Vancouver that subjected the structures to 20 earthquake records, 6-storey wood-frame building is expected to show similar or smaller inter-storey drift than a 4-storey wood-frame building, which is currently deemed acceptable under the current building code. Building construction - Design Building construction - Specfications Earthquakes, Effect on building construction
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Investigating the Performance of Wood Portal Frames as Alternative Bracing Systems in Light-Frame Wood Buildings

https://research.thinkwood.com/en/permalink/catalogue2240
Year of Publication
2012
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
LSL (Laminated Strand Lumber)
Application
Frames
Author
Al Mamun, Abdullah
Organization
University of Ottawa
Year of Publication
2012
Format
Thesis
Material
LVL (Laminated Veneer Lumber)
LSL (Laminated Strand Lumber)
Application
Frames
Topic
Mechanical Properties
Keywords
Portal Frames
Shear Walls
FE model
Moment Capacity
Stiffness
Lateral Load
Research Status
Complete
Summary
Light-frame shearwall assemblies have been successfully used to resist gravity and lateral loads, such as earthquake and wind, for many decades. However, there is a need for maintaining the structural integrity of such buildings even when large openings in walls are introduced. Wood portal frame systems have been identified as a potential alternative to meet some aspects of this construction demand. The overarching goal of the research is to develop wood portal frame bracing systems, which can be used as an alternative or in combination with light-frame wood shearwalls. This is done through investigating the behavior of wood portal frames using the MIDPLY shearwall framing technique. A total of 21 MIDPLY corner joint tests were conducted with varying bracing details. Also, a finite element model was developed and compared with test results from the current study as well as studies by others. It was concluded from the corner joint tests that the maximum moment resistance increased with the addition of metal straps or exterior sheathings. The test results also showed a significant increase in the moment capacity and rotational stiffness by replacing the Spruce-Pine Fir (SPF), header with the Laminated Veneer Lumber (LVL) header. The addition of the FRP to the standard wall configuration also resulted in a significant increase in the moment capacity. However, no significant effect was observed on the stiffness properties of the corner joint. The FE model was capable of predicting the behavior of the corner joints and the full-scale portal frames with realistic end-conditions. The model closely predicted the ultimate lateral capacity for all the configurations but more uncertainty was found in predicting the initial stiffness.The FE model used to estimate the behavior of the full-scale portal frames constructed using the MIDPLY framing techniques showed a significant increase in the lateral load carrying capacity when compared with the traditional portal frame. It was also predicted using the full-scale FE model that the lateral load carrying capacity of the MIDPLY portal frame would increase with the addition of the metal straps on exterior faces. A parametric study showed that using a Laminated Strand Lumber (LSL) header increased the lateral load carrying capacity and the initial stiffness of the frames relative to the SPF header. The study also showed that there was an increase in the capacity if high strength metal straps were used. Doubling of the nail spacing at header and braced wall segment had a considerable effect on the lateral capacity of portal frame. Also, the initial stiffness was reduced for all the configurations with the doubling of the nail spacing at the header and braced wall segment in comparison with the reference frame.
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Carterton Events Centre Auditorium Pres-Lam Wall Design and Construction

https://research.thinkwood.com/en/permalink/catalogue38
Year of Publication
2012
Topic
Seismic
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Shear Walls
Author
Dekker, Dave
Chung, Stanley
Palermo, Alessandro
Year of Publication
2012
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Shear Walls
Topic
Seismic
Keywords
Lateral Loads
Post-Tensioned
Pres-Lam
Sustainability
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
April 13-15, 2012, Christchurch, New Zealand
Summary
Driven by sustainability, locally available resources and expertise, and economy, the design of the Carterton Events Centre focused on timber for the majority of the main structural and non-structural components. Combined with a client desire for minimization of earthquake damage, dissipative post-tensioned rocking Laminated Veneer Lumber (LVL) shear walls (Pres-Lam) were considered for the lateral load resisting system. During design development various structural forms were explored and tested through costing to determine an economic design solution meeting the project drivers. Advanced numerical analyses carried out by the University of Canterbury validated the design process assuring confidence with the design of the technology.
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Damage Assessment of Cross Laminated Timber Connections Subjected to Simulated Earthquake Loads

https://research.thinkwood.com/en/permalink/catalogue70
Year of Publication
2012
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Schneider, Johannes
Stiemer, Siegfried
Tesfamariam, Solomon
Karacabeyli, Erol
Popovski, Marjan
Year of Publication
2012
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Connections
Seismic
Keywords
Damage
Panels
North American Market
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
July 15-19, 2012, Auckland, New Zealand
Summary
Wood-frame is the most common construction type for residential buildings in North America. However, there is a limit to the height of the building using a traditional wood-frame structure. Cross-laminated timber (CLT) provides possible solutions to mid-rise and high-rise wood buildings. CLT offers many advantages such as improved dimensional stability, a quicker erection time and good performance in case of fire. In order to introduce the cross-laminated timber products to the North American market, it is important to gain a comprehensive understanding of its structural properties. This paper focuses on the seismic performance of CLT connections. Over the last few years FPInnovations of Canada has conducted a test program to determine the structural properties of CLT panels and its application in shear walls. The test program comprised of more than 100 connection tests which followed the loading procedures of CUREE and ISO test protocols as specified in ASTM Standards ASTM E 2126-09 (2009). These tests were performed parallel and perpendicular to the grain of the outer layer, respectively. The impact of different connections on the seismic performance of CLT walls was investigated in a second phase on full size shearwall. CLT panels are relatively stiff and thus energy dissipation must be accomplished through the ductile behaviour of connections between different shear wall elements and the connections to the story below. A literature review on previous research work related to damage prediction and assessment for wood frame structures was performed. Different approaches for damage indices were compared and discussed. This paper describes how the energy-based cumulative damage assessment model was calibrated to the CLT connection and shear wall test data in order to investigate the damage under monotonic and cyclic loading. Comparison of different wall setup provided a deeper insight into the damage estimation of CLT shear walls and determination of the key parameters in the damage formulation. This represents a first published attempt to apply the damage indices to estimate the seismic behaviour of CLT shear walls.
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Wood-Steel Hybrid Seismic Force Resisting Systems: Seismic Ductility

https://research.thinkwood.com/en/permalink/catalogue330
Year of Publication
2012
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Author
Dickof, Carla
Stiemer, Siegfried
Tesfamariam, Solomon
Organization
University of British Columbia
Year of Publication
2012
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Topic
Design and Systems
Keywords
Timber-Steel Hybrid
Overstrength
Ductility
Stiffness
Seismic Force Resisting System
Pushover Response
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
July 15-19, 2012, Auckland, New Zealand
Summary
North American building codes currently provide strict limits on height of wood structures, where for example, in Canada wood structures are limited to 4 or 5 storeys. This paper examines wood-steel hybrid system to increase seismic force resistance beyond current limits, up to 10 storeys. The use wood-steel hybrid systems allows for the combination of high strength and ductility of steel with high stiffness and light weight of timber. This paper examines one type o wood and steel hybrid system: a steel moment frame with infill crossed Laminated Timber (CLT) shear walls. A detailed non-linear model of a 2D wood-steel hybrid seismic force resisting system was completed for 6, and 9 storeys; with two different steel frame designs, and four different placements of the infill walls. The static pushover response of this type of hybrid seismic force resisting system (SFRS) has been completed and compared for all cases. The results indicate that preliminary values for ductility (Rd) and overstrength (Ro) for this type of system are 2.0 and 1.7, respectively, similar to a plain wood wall system. Low ductility frames benefit the most from the addition of CLT shear walls as they do not lose the ductility in the system.
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Experimental Testing of Anchoring Devices for Bottom Rail in Partially Anchored Timber Frame Shear Walls with Two-Sided Sheathing

https://research.thinkwood.com/en/permalink/catalogue400
Year of Publication
2012
Topic
Connections
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Author
Caprolu, Giuseppe
Organization
Luleå University of Technology
Year of Publication
2012
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Connections
Keywords
Failure Modes
Sheathing
Research Status
Complete
Summary
Källsner and Girhammar have presented a new plastic design method for wood-framed shear walls at ultimate limit state. This method allows the designer to calculate the load-carrying capacity of shear walls partially anchored, where the leading stud is not fully anchored against uplift. The anchorage system of shear walls is provided from anchor bolts and hold downs. Anchor bolts provide horizontal shear continuity between the bottom rail and the foundation. Hold downs are directly connected from the vertical end stud to the foundation. When hold downs are not provided, the bottom row of nails transmits the vertical forces in the sheathing to the bottom rail (instead of the vertical stud) where the anchor bolts will further transmit the forces into the foundation. Because of the eccentric load transfer, due to forces acting in the same vertical plane, transverse bending is created in the bottom rail and splitting often occurs. It is important to evaluate this cross-wise bending and to ensure that no brittle failure occur in the bottom rail. The bottom rail is experimentally studied with respect to two primary failure modes, splitting along the bottom of the bottom rail due to cross-wise bending and splitting along the edge side of the bottom rail due forces perpendicular to the grain from the sheathing-to-framing connections. The parameters varied are the size of the washer and the orientation of the pith. The bottom rail was subjected to loading perpendicular to grain through two-sided sheathing. In this report the different set of series are presented. Five sets were conducted depending on the size of the washer and in each set the pith was placed upwards and downwards. The tests showed three different failure modes. In addition to the failure modes that the testing program was aimed at, splitting along the bottom or side of the bottom rail, the final failure was also due to plastic bending and withdrawal of the sheathing-to-framing nails. The results show that the size of the washer has a significant influence on the maximum load and the failure modes. The results show also that the orientation of the pith have a significant influence on the maximum load.
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Experimental Testing of Hold Down Devices for Timber Frame Shear Walls

https://research.thinkwood.com/en/permalink/catalogue401
Year of Publication
2012
Topic
Connections
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Author
Caprolu, Giuseppe
Organization
Luleå University of Technology
Year of Publication
2012
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Connections
Keywords
Hold-Down
Strength
Stiffness
Research Status
Complete
Summary
Källsner and Girhammar have presented a new plastic design method for wood-framed shear walls at ultimate limit state. This method allows the designer to calculate the load-carrying capacity of partially anchored shear walls, where the leading stud is not anchored against uplift. The anchorage system of shear walls is provided by anchor bolts in the bottom rail and hold downs at the leading stud. Anchor bolts provide horizontal shear continuity between the bottom rail and the foundation. Hold downs are directly connecting the vertical leading stud to the foundation. Sometimes hold downs are not provided and only the bottom rail is anchored to the substrate. In this case the bottom row of nails transmits the vertical forces in the sheathing to the bottom rail (instead of the stud) where the anchor bolts will further transmit the forces into the foundation. In this report hold downs have been experimentally studied with respect to the strength and stiffness of the connection. Four different types of hold downs have been tested. The specimen was subjected to tension load applied to the stud. Four tests series are presented. Each series was divided into different sets according to the type of fastener used with the hold down device. The results show that the failure load is higher when hold downs with anchor bolts are used, up to ten times higher than the anchorage that uses only screws or nails. The failure mode vary with the type of hold down and the type of fasteners used. The tests showed three primary failure modes: failure of the stud when a bolt is used as the fastener between hold down device and stud, failure due to pull-out of the screws or nails from the rail and failure due to failure or pull-out of screws or nails from stud. Also, failure of the stud itself occurred in some tests caused by some defect of the timber.
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Experimental Analysis of Composite Timber-Concrete Wall Element

https://research.thinkwood.com/en/permalink/catalogue905
Year of Publication
2012
Topic
Design and Systems
Material
Timber-Concrete Composite
Application
Walls
Author
Hassan, Osama
Schedin, Staffan
Girhammar, Ulf
Year of Publication
2012
Format
Conference Paper
Material
Timber-Concrete Composite
Application
Walls
Topic
Design and Systems
Keywords
Nail Plate
shear connectors
Conference
European Conference on Composite Materials
Research Status
Complete
Notes
June 24-28, 2012, Venice, Italy
Summary
The authors present an experimental and theoretical study on a composite or hybrid element used in residential and agricultural buildings. The composite wall element consists of timber studs connected to a concrete plate by means of nail plate shear connectors. Experimental results are presented and compared with an analytical model for partial composite action. A good agreement is obtained between the analytical and experimental results. Also, some suggestions to improve the design of the composite element are discussed.
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Ambient and Forced Vibration Testing and Finite Element Model Updating of a Full-Scale Posttensioned Laminated Veneer Lumber Building

https://research.thinkwood.com/en/permalink/catalogue1103
Year of Publication
2012
Topic
Seismic
Wind
Acoustics and Vibration
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Shear Walls
Author
Worth, Margaret
Omenzetter, Piotr
Morris, Hugh
Year of Publication
2012
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Shear Walls
Topic
Seismic
Wind
Acoustics and Vibration
Keywords
Post-Tensioned
Full Scale
In Situ
Finite Element Model
Dynamic Performance
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
April 13-15, 2012, Christchurch, New Zealand
Summary
The Nelson Marlborough Institute of Technology Arts and Media building was completed in 2011 and consists of three seismically separate complexes. This research focussed on the Arts building as it showcases the use of coupled post-tensioned timber shear walls. These are part of the innovative Expan system. Full-scale, in-situ dynamic testing of the novel building was combined with finite element modelling and updating to obtain an understanding of the structural dynamic performance within the linear range. Ambient testing was performed at three stages during construction and was combined with forced vibration testing for the final stage. This forms part of a larger instrumentation program developed to investigate the wind and seismic response and long term deformations of the building. A finite element model of the building was formulated and updated using experimental modal characteristics. It was shown that the addition of non-structural elements, such as cladding and the staircase, increased the natural frequency of the first mode and the second mode by 19% and 24%, respectively. The addition of the concrete floor topping as a structural diaphragm significantly increased the natural frequency of the first mode but not the second mode, with an increase of 123% and 18%, respectively. The elastic damping of the NMIT building at low-level vibrations was identified as being between 1.6% and 2.4%.
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In-Plane Stiffness of Cross-Laminated Timber Floors

https://research.thinkwood.com/en/permalink/catalogue1263
Year of Publication
2012
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Shear Walls
Author
Ashtari, Sepideh
Organization
University of British Columbia
Year of Publication
2012
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Floors
Shear Walls
Topic
Mechanical Properties
Keywords
In-Plane Stiffness
Numerical Model
Self-Tapping Screws
Panel-to-Panel
In-Plane Shear Modulus
Stiffness
Research Status
Complete
Summary
This study investigates the in-plane stiffness of CLT floor diaphragms and addresses the lateral load distribution within buildings containing CLT floors. In practice, it is common to assume the floor diaphragm as either flexible or rigid, and distribute the lateral load according to simple hand calculations methods. Here, the applicability of theses assumption to CLT floor diaphragms is investigated. There is limited number of studies on the subject of in-plane behaviour of CLT diaphragms in the literature. Many of these studies involve testing of the panels or the connections utilized in CLT diaphragms. This study employs numerical modeling as a tool to address the in-plane behaviour of CLT diaphragms. The approach taken to develop the numerical models in this thesis has not been applied so far to CLT floor diaphragms. Detailed 2D finite element models of selective CLT floor diaphragm configurations are generated and analysed in ANSYS. The models contain a smeared panel-to-panel connection model, which is calibrated with test data of a special type of CLT connection with self-tapping wood screws. The floor models are then extended to building models by adding shearwalls, and the lateral load distribution is studied for each building model. A design flowchart is also developed to aid engineers in finding the lateral load distribution for any type of building in a systematic approach. By a parametric study, the most influential parameters affecting the in-plane behaviour of CLT floor diaphragm and the lateral load distribution are identified. The main parameters include the response of the CLT panel-to-panel connections, the in-plane shear modulus of CLT panels, the stiffness of shearwalls, and the floor diaphragm configuration. It was found that the applicability of flexible or rigid diaphragm assumptions is primarily dependent on the relative stiffness of the CLT floor diaphragm and the shearwalls.
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Design Example: Wood Diaphragm Using Envelope Method

https://research.thinkwood.com/en/permalink/catalogue2613
Year of Publication
2013
Topic
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Shear Walls
Author
Neylon, B.
Wang, Jasmine
Ni, Chun
Organization
FPInnovations
Year of Publication
2013
Format
Report
Material
Glulam (Glue-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Design and Systems
Keywords
Shear
Diaphragm
Low-Rise
Commercial
Research Status
Complete
Summary
This building is a typical one-storey commercial building located in Vancouver, BC. The plan dimensions are 30.5 m x 12.2 m (100’ x 40’), with a building height of 5 m. The walls are wood-based shear walls, with a wood diaphragm roof and a steel moment frame at the storefront. The roof plan is shown in Figure 1. The site is Seismic Class ‘C’. Wind, snow and seismic figures specific to the project location are taken from the current version of the British Columbia Building Code (2012). Roof dead load is assumed to be 1.0 kPa and the wall weight is 0.5 kPa. The weight of non-structural items including mechanical equipment and the storefront façade has not been included in this example for simplicity.
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Dynamic Testing and Numerical Modeling of Residential Building Modules

https://research.thinkwood.com/en/permalink/catalogue105
Year of Publication
2013
Topic
Design and Systems
Mechanical Properties
Material
Light Frame (Lumber+Panels)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Author
Jørstad, Anders
Organization
Norwegian University of Science and Technology
Publisher
Institutt for konstruksjonsteknikk
Year of Publication
2013
Format
Thesis
Material
Light Frame (Lumber+Panels)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Mechanical Properties
Keywords
Finite Element Model
Tall Wood
Testing
Modal Analysis
Modules
Research Status
Complete
Summary
This thesis was initiated by a project planing the world's tallest timber building in Bergen, Norway, (the VHT project). The concept of the building is based on a load baring glulam frame with building modules stacked inside to create the residential area of the building. Calculation done by Sweco showed that more damping was needed to lower the accelerations in the top floor of the building. Since little was known about the dynamic properties of building modules and whether these could be used to increase the damping of the building, a survey was wanted. In this master thesis the dynamic properties of the building modules have been evaluated. This has been done by preforming dynamic test on building modules similar to those planed for the VHT project. Two test protocols were used to test the modules, an experimental modal analysis method using a modal hammer and a system identification method. The goal of the tests was to identify the modal frequencies, damping ratios and mode shapes of the building modules.The tested modules were modeled in a finite element (FE) method program and scaled to fit the size of the VHT modules. This way the dynamic properties of the VHT modules could be estimated. Simple shear frame models of the VHT modules were made to be implemented in a larger model of the VHT building to evaluate the effect of the modules on the entire structure. Several detailed FE models were made to evaluate how the separate parts of the modules influenced the dynamic response of the modules. An evaluation of the dynamic properties of the sound reducing material Stepisol was also done by dynamic testing in the lab and FE modeling. It was found that the tested modules had two translational modes and one torsional mode. The overall damping ratio of the modules was found to be roughly 3%. From the numerical tests the stiffness of the module walls were found to be more or less constant per meter wall. The walls can therefor easily be scaled for similar modules with different dimensions to predict the dynamic properties of the new modules.The Stepisol was found to influence the dynamic properties of the stacked building modules severely. The lab tests showed that Stepisol has a high material damping that helps increasing the damping in the modules. The FE models showed that layers of Stepisol makes the stacked modules a lot less stiff and it is a key feature that can be used to alter the dynamic behavior of stacked modules.
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Seismic Design of a 10-Storey CLT Building

https://research.thinkwood.com/en/permalink/catalogue384
Year of Publication
2013
Topic
Design and Systems
Seismic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Follesa, Maurizio
Vassallo, Davide
Christovasilis, Ioannis
Organization
FPInnovations
Year of Publication
2013
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Seismic
Connections
Keywords
Finite Element Model
Equivalent Seismic Force Procedure
Modal Response Spectrum Method
Research Status
Complete
Summary
This report presents the seismic design of a 10-storey Cross Laminated Timber (CLT) building in Vancouver, BC, conducted according to the National Building Code of Canada. The multi-storey condominium consists of 20 apartments for a total floor area of about 2000 m2. First, a preliminary simplified model is formulated assuming the same stiffness per meter for each wall of the building. The Equivalent Seismic Force Procedure is applied and the results serve for a preliminary design of all the major connections that play a significant role on the lateral stiffness of the building, assuming rigid in plane floor diaphragms and well-anchored CLT walls. Based on the results of the preliminary design, a 3 dimensional finite element model is created, describing analytically the modelling approach adopted, and both the Equivalent Seismic Force Procedure (referred as static analysis) and the Modal Response Spectrum Method (referred as dynamic analysis) are applied to obtain the design forces for each wall of the building. Based on the results from the dynamic analysis, the final seismic design of the building is performed and the results are presented for connections dedicated to transfer (i) shear forces from floor diaphragms to walls below and from walls to diaphragms below, (ii) uplift forces for each wall, (iii) boundary forces between CLT panels within the same walls, (iv) boundary forces between perpendicular walls, and (v) boundary forces between CLT floor panels. All connections prescribed to provide ductility and energy dissipation are designed to fail in ductile failure mode according to the CSA 086-09 while connections that should remain within the elastic range to allow the ductile connections to yield are designed with overstrength factor.
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A Mechanics Based Approach for Determining Deflections of Stacked Multi-Storey Wood Based Shear Walls

https://research.thinkwood.com/en/permalink/catalogue738
Year of Publication
2013
Topic
Mechanical Properties
Serviceability
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Shear Walls
Author
Newfield, Grant
Ni, Chun
Wang, Jasmine
Organization
Canadian Wood Council
FPInnovations
Year of Publication
2013
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Shear Walls
Topic
Mechanical Properties
Serviceability
Keywords
Multi-Storey
Deflection
Flexural Deformations
Shear
Research Status
Complete
Summary
The 2009 edition of CSA Standard O86, Engineering Design in Wood (CSA 2009), provides an equation for determining the deflection of shear walls. It is important to note that this equation only works for a single-storey shear wall with load applied at the top of the wall. While the equation captures the shear and flexural deformations of the shear wall, it does not account for moment at the top of the wall and the cumulative effect due to rotation at the bottom of the wall, which would be expected in a multi-storey structure. In this fact sheet, a mechanics-based method for calculating deflection of a multi-storey wood-based shear wall is presented.
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Design Example: Design of Stacked Multi-Storey Wood Shear Walls Using a Mechanics Based Approach

https://research.thinkwood.com/en/permalink/catalogue739
Year of Publication
2013
Topic
Design and Systems
Mechanical Properties
Seismic
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Shear Walls
Author
Newfield, Grant
Ni, Chun
Wang, Jasmine
Organization
Canadian Wood Council
FPInnovations
Year of Publication
2013
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Shear Walls
Topic
Design and Systems
Mechanical Properties
Seismic
Keywords
Codes
National Building Code of Canada
Lateral Seismic Loads
Research Status
Complete
Summary
Figure 1 shows a floor plan and elevation along with the preliminary shear wall locations for a sixstorey wood-frame building. It is assumed some preliminary calculations have been provided to determine the approximate length of wall required to resist the lateral seismic loads. If the preliminary design could not meet the drift limit requirement using the base shear obtained based on the actual period, the shear walls should be re-designed until the drift limit requirement is satisfied.
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Linear Dynamic Analysis for Wood-Based Shear Walls and Podium Structures: Part 1: Developing Input Parameters for Linear Dynamic Analysis

https://research.thinkwood.com/en/permalink/catalogue740
Year of Publication
2013
Topic
Design and Systems
Mechanical Properties
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Author
Ni, Chun
Newfield, Grant
Wang, Jasmine
Organization
FPInnovations
Year of Publication
2013
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Design and Systems
Mechanical Properties
Keywords
Deflection
Linear Dynamic Analysis
National Building Code of Canada
Stiffness
Floor Drifts
Research Status
Complete
Summary
Utilizing Linear Dynamic Analysis (LDA) for designing steel and concrete structures has been common practice over the last 25 years. Once preliminary member sizes have been determined for either steel or concrete, building a model for LDA is generally easy as the member sizes and appropriate stiffness can be easily input into any analysis program. However, performing an LDA for a conventional wood-frame structure has been, until recently, essentially non-existent in practice. The biggest challenge is that the stiffness properties required to perform an LDA for a wood-based system are not as easily determined as they are for concrete or steel structures. This is mostly due to the complexities associated with determining the initial parameters required to perform the analysis. With the height limit for combustible construction limited to four stories under the National Building Code of Canada, it was uncommon for designers to perform detailed analysis to determine the stiffness of shear walls, distribution of forces, deflections, and inter-storey drifts. It was only in rare situations where one may have opted to check building deflections. With the recent change in allowable building heights for combustible buildings from four to six storeys under an amendment to the 2006 BC Building Code, it has become even more important that designers consider more sophisticated methods for the analysis and design of wood-based shear walls. As height limits increase, engineers should also be more concerned with the assumptions made in determining the relative stiffness of walls, distribution of forces, deflections, and inter-storey drifts to ensure that a building is properly detailed to meet the minimum Code objectives. Although the use of LDA has not been common practice, the more rigorous analysis, as demonstrated in the APEGBC bulletin on 5- and 6-storey wood-frame residential building projects (APEGBC 2011), could be considered the next step which allows one to perform an LDA. This fact sheet provides a method to assist designers who may want to consider an LDA for analyzing wood-frame structures. It is important to note that while LDA may provide useful information as well as streamline the design of wood-frame structures, it most often will not be necessary.
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Study on Seismic Performance of Building Structure with Cross Laminated Timber: Part 13: Relative Story Displacement of Full Scale 3-Story Model -Comparisons with Shaking Table Test

https://research.thinkwood.com/en/permalink/catalogue982
Year of Publication
2013
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Yahaura, Sota
Goto, Hiroshi
Hamamoto, Takashi
Gosei, Murakami
Miyake, Tatsuya
Matsumoto, Kazuyuki
Kaiko, Naoto
Organization
Architectural Institute of Japan
Year of Publication
2013
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Keywords
Static Load Tests
Shaking Table Test
Shear Force
Seismic Performance
Research Status
Complete
Summary
The material presented in this paper refers to a part of the investigation on cross-laminated (XLam) wall panel systems subjected to seismic excitation, carried out within the bilateral project realized by the Institute of Earthquake Engineering and Engineering Seismology (IZIIS) and the Faculty of Civil and Geodetic Engineering at the University of Ljubljana (UL FCGE). The full program of the research consista of basic tests of small XLam wooden blocks and quasi-static tests of anchors, then quasi-static tests of full-scale wall panels with given anchors, shaking-table tests of two types of XLam systems including ambient-vibration tests, and finally analytical research for the definition of the computational model for the analysis of these structural systems. In this paper, the full-scale shaking-table tests for one XLam system type (i.e. specimen 1 consisting of two single-unit massive wooden XLam panels) that have been performed in the IZIIS laboratory are discussed. The principal objectives of the shaking-table tests have been to get an insight into the behavior of the investigated XLam panel systems under seismic excitations, develop a physical and practical computational model for simutalion of the dynamic response based on the tests, and finally correlate the results with those from the previously performed quasi-static tests on the same wooden panel types. The obtained experimental results have been verified using a proposed computational model that included new contitutive relationships for anchors and contact zones between panels and foundations. Because a reasonable agreement between the numerical and experimental results has been achieved, the proposed computational model is expected to provide a solid basis for future research on the practical design of these relatively new materials and systems.
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Study on Seismic Performance of Building Structure with Cross Laminated Timber: Part 12: Objective and Loading Procedure and Accuracy of Static Loading Test

https://research.thinkwood.com/en/permalink/catalogue983
Year of Publication
2013
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Kaiko, Naoto
Hamamoto, Takashi
Gosei, Murakami
Yahaura, Sota
Miyake, Tatsuya
Goto, Hiroshi
Nakagawa, Takafumi
Yasumura, Motoi
Organization
Architectural Institute of Japan
Year of Publication
2013
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Keywords
Static Loading Test
Failure Behavior
Shear Force
Seismic Performance
Research Status
Complete
Summary
Cross-laminated timber (CLT) is a relatively new heavy timber construction material (also referred to as massive timber) that originated in central Europe and quickly spread to building applications around the world over the past two decades. Using dimension lumber (typically in the range of 1× or 2× sizes) glue laminated with each lamination layer oriented at 90° to the adjacent layer, CLT panels can be manufactured into virtually any size (with one dimension limited by the width of the press), precut and pregrooved into desirable shapes, and then shipped to the construction site for quick installation. Panelized CLT buildings are robust in resisting gravity load (compared to light-frame wood buildings) because CLT walls are effectively like solid wood pieces in load bearing. The design of CLT for gravity is relatively straightforward for residential and light commercial applications where there are plenty of wall lines in the floor plan. However, the behavior of panelized CLT systems under lateral load is not well understood especially when there is high seismic demand. Compared to light-frame wood shear walls, it is relatively difficult for panelized CLT shear walls to achieve similar levels of lateral deflection without paying special attention to design details, i.e., connections. A design lacking ductility or energy dissipating mechanism will result in high acceleration amplifications and excessive global overturning demands for multistory buildings, and even more so for tall wood buildings. Although a number of studies have been conducted on CLT shear walls and building assemblies since the 1990s, the wood design community’s understanding of the seismic behavior of panelized CLT systems is still in the learning phase, hence the impetus for this article and the tall CLT building workshop, which will be introduced herein. For example, there has been a recent trend in engineering to improve resiliency, which seeks to design a building system such that it can be restored to normal functionality sooner after an earthquake than previously possible, i.e., it is a resilient system. While various resilient lateral system concepts have been explored for concrete and steel construction, this concept has not yet been realized for multistory CLT systems. This forum article presents a review of past research developments on CLT as a lateral force-resisting system, the current trend toward design and construction of tall buildings with CLT worldwide, and attempts to summarize the societal needs and challenges in developing resilient CLT construction in regions of high seismicity in the United States.
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Strength Properties of CLT Composed of Sugi Laminations : (9) Small Scale CLT Shear Wall

https://research.thinkwood.com/en/permalink/catalogue984
Year of Publication
2013
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Watanabe, Hiroshi
Araki, Yasuhiro
Nakajima, Shiro
Miyattaki, Atsushi
Yasumura, Motoi
Ando, Naoto
Kaiko, Naoto
Organization
Architectural Institute of Japan
Year of Publication
2013
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Mechanical Properties
Keywords
In-Plane Shear Force
Strength Properties
Sugi
Research Status
Complete
Summary
An investigation was carried out on CLT panels made from Sitka spruce in order to establish the effect of the thickness of CLT panels on the bending stiffness and strength and the rolling shear. Bending and shear tests on 3-layer and 5-layer panels were performed with loading in the out-of-plane and in-plane directions. ‘Global’ stiffness measurements were found to correlate well with theoretical values. Based on the results, there was a general tendency that both the bending strength and rolling shear decreased with panel thickness. Mean values for rolling shear ranged from 1.0 N/mm2 to 2.0 N/mm2.
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Free
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Experimental and Numerical Analyses of New Massive Wooden Shear-Wall Systems

https://research.thinkwood.com/en/permalink/catalogue93
Year of Publication
2014
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Pozza, Luca
Scotta, Roberto
Trutalli, Davide
Pinna, Mario
Polastri, Andrea
Bertoni, Paolo
Publisher
MDPI
Year of Publication
2014
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Quasi-Static
Cyclic Loading Tests
Numerical model
Ductility
Eurocode 8
Behaviour Factor
Dissipative Capacity
Research Status
Complete
Series
Buildings
Summary
Three innovative massive wooden shear-wall systems (Cross-Laminated-Glued Wall, Cross-Laminated-Stapled Wall, Layered Wall with dovetail inserts) were tested and their structural behaviour under seismic action was assessed with numerical simulations. The wall specimens differ mainly in the method used to assemble the layers of timber boards composing them. Quasi-static cyclic loading tests were carried out and then reproduced with a non-linear numerical model calibrated on the test results to estimate the most appropriate behaviour factor for each system. Non-linear dynamic simulations of 15 artificially generated seismic shocks showed that these systems have good dissipative capacity when correctly designed and that they can be assigned to the medium ductility class of Eurocode 8. This work also shows the influence of deformations in wooden panels and base connectors on the behaviour factor and dissipative capacity of the system.
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